Title: Cache disappears Last modified: August 29, 2023 --- # Cache disappears * Resolved [lira123](https://wordpress.org/support/users/lira123/) * (@lira123) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/) * Hi! I have this problem with all my sites since last update and it is that half the cached pages disappears after a couple of hours. Lets say the normal current cache size is 30 MB, now when I check that number after a couple of hours its down to around 15 MB and I have to preload the cache again manually for the missing pages. Its like the plugin loses half the cache out of nowhere. * I have not seen this before, any idea of what could cause this? Viewing 11 replies - 1 through 11 (of 11 total) * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17013164) * What is your cache lifespan set to? * Did you publish or update URLs, such as posts/pages/custom post types including any other content related to it (i.e. home, category, tag, etc.) * Do you have minify enabled? * Thread Starter [lira123](https://wordpress.org/support/users/lira123/) * (@lira123) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17013200) * Between 30-45 days depending on the site. * No, I have not updating anything on the sites when this occurs. Two of the sites with this problem is not updated since june. * Minify is enabled on one site, not the others. But the problem occurs on all sites. * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17016362) * The cache is automatically purged after these actions: [https://snipboard.io/ebhr62.jpg](https://snipboard.io/ebhr62.jpg) * So, cache may be purged if any of the following happen, you change theme, you update your mens, you update any widgets, upgrade themes/plugin/core/, you add a WPML string translation etc.  It is likely one of the events in the screenshot occurred and cache was purged. * Thread Starter [lira123](https://wordpress.org/support/users/lira123/) * (@lira123) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17016422) * Thanks for the reply, but thats not the problem. I’ve used WP Optimize for 2 years so I know that certain actions purges the cache. This is something else, all my sites gets their cache purges every 24 hours now, even though the cache time is 30 days and the site is untouched. Its like the cache time is overruled and set to 1 day. * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17019535) * Can you install the free pluginWP Control’ plugin and then wait for 24 hours to see if the issue occurs again. If possible could you avoid making any changes to the site, such as activating or deactivating any plugins, updating plugin settings, and so on. After 24 hours, if the issue reoccurs, can you take a screenshot of your cron events. * It would be really useful if you could all do this as we might be able to see if there is a common event that happens on all of your sites that may be triggering a purge/preload * Thread Starter [lira123](https://wordpress.org/support/users/lira123/) * (@lira123) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17019584) * Absolutely, will do that! * Thread Starter [lira123](https://wordpress.org/support/users/lira123/) * (@lira123) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17020960) * [@vupdraft](https://wordpress.org/support/users/vupdraft/) I found whats causing the purge, its something called: * Name: wpo_reset_webp_conversion_test_result * Action: `WPO_WebP_Cron_Scheduler->reset_webp_conversion_flags()` * This is a daily action that happened at the same time the purge happened. I also double checked it with a manual activation within the WP Crontol plugin and it indeed purged the cache. So its looks like its something from the WP-Optimize plugin. What does this do and is it possible to turn it off? * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17025050) * Hi, * The cron event is for resetting the WebP conversion method so as a workaround you could try switching off the option to create WebP images in the Images tab. I will pass your findings onto our development so that we can look at providing a permanent fix. * [eugene212](https://wordpress.org/support/users/eugene212/) * (@eugene212) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17031937) * I observe the same – wpo_reset_webp_conversion_test_result cron event is scheduled to be run on a daily basis and, indeed, it clears page cache… * Unfortunately this event is sticky and does not disappear regardless of “create WebP images” option setting (at least in my case). * I understand that WP-Optimize development team will be working on the potential permanent fix, but is it possible to have some simple code snippet to deal with the issue of undesired cache clearing meanwhile ? - This reply was modified 2 years, 8 months ago by [eugene212](https://wordpress.org/support/users/eugene212/). * [webpart](https://wordpress.org/support/users/webpart/) * (@webpart) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17035135) * Hi, * We have exactly the same problem occurring on our sites on Windows webserver. * Plugin Support [vupdraft](https://wordpress.org/support/users/vupdraft/) * (@vupdraft) * [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17042592) * Hi, * I think I have just replied to you in your other thread. Thank you for the report, we are currently investigations this. Viewing 11 replies - 1 through 11 (of 11 total) The topic ‘Cache disappears’ is closed to new replies. * ![](https://ps.w.org/wp-optimize/assets/icon-256x256.png?rev=1552899) * [WP-Optimize – Cache, Compress images, Minify & Clean database to boost page speed & performance](https://wordpress.org/plugins/wp-optimize/) * [Frequently Asked Questions](https://wordpress.org/plugins/wp-optimize/#faq) * [Support Threads](https://wordpress.org/support/plugin/wp-optimize/) * [Active Topics](https://wordpress.org/support/plugin/wp-optimize/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/wp-optimize/unresolved/) * [Reviews](https://wordpress.org/support/plugin/wp-optimize/reviews/) * 11 replies * 7 participants * Last reply from: [vupdraft](https://wordpress.org/support/users/vupdraft/) * Last activity: [2 years, 8 months ago](https://wordpress.org/support/topic/cache-disappears/#post-17042592) * Status: resolved